Extraction of polyunsaturated fatty acid methyl esters by imidazolium-based ionic liquids containing silver tetrafluoroborate-Extraction equilibrium studies

作者：Li Min; Pittman Charles U Jr; Li Tingyu^*

来源：Talanta, 2009, 78(4-5): 1364-1370.

DOI：10.1016/j.talanta.2009.02.011

• Liquid phase extraction
• Ionic liquids
• Polyunsaturated fatty acid methyl ester
• Distribution ratio
• Extraction isotherm
• Separation

The extraction/enrichment of omega - 3 polyunsaturated fatty acid methyl esters (PUFAMEs) by hydrophobic ionic liquids (ILs) containing silver salts as the extraction phase has been extended to include equilibrium studies. The extraction time, organic solvents, IL structures, and AgBF(4) concentrations all influence the organic/ionic liquid biphasic extraction equilibrium. Each of these parameters was studied. The PUFAME distribution ratios, partition coefficients and the PUFAME-Ag(+) complex stability constants were determined from gas chromatography (GC) analyses. When AgBF(4) dissolved in [hmim][PF(6)]was used as the extraction phase, both the distribution ratios of PUFAMEs and the stability constants of PUFAME-Ag(+) complexes increased significantly with an increase in the degree of unsaturation of the PUFAMEs. Investigation of the IL structures indicated that larger PUFAME distribution ratios were obtained when AgBF(4) was dissolved in hydrophobic ILs than in hydrophilic ILs. Higher PUFAME distribution ratios occurred using shorter chain alkanes as the organic solvents. The extraction isotherms for PUFAME uptake were obtained from which saturated extraction capacities were determined. Compared with previous aqueous AgNO(3) extractions, a more efficient extraction of PUFAMEs was obtained by using a hydrophobic IL containing AgBF(4). Much higher extraction capacities and significant shorter operation times were also achieved.

• 出版日期2009-6-15